EP1588786A1 - Straw chopper blade and counter-blade for a straw chopper and method of manufacturing thereof - Google Patents

Abstract

The process involves rolling a longitudinal edge of a flat strip into a prismatic shape with a slightly rounded cutting edge to obtain a chopping blade with a prismatic cutting edge of satisfactory sharpness. The blade with a section of flat steel having a fastening zone and prismatic cutting edge (15, 16). Serrations are formed over an entire length of the edge, and zone-hardening is carried out over the length of the edge.

Description

Field of the invention

The invention relates to a method for producing so-called chopping blades according to The preamble of claim 1 and chopper knife with the preamble of claim 15 and counter knife according to the preamble of claim 22 for a chopping device.

Background of the invention

Such knives are used in shredders - generally in shredders of straw and the like - used. Such devices can be found, for example on combines. They are provided with a rotating roller or drum, where a variety of chopping blades are fixed or pendulum and arranged Although distributed over both the drum length and the drum circumference. These Devices chop the supplied material to be cut between the moving blades and the fixed counter knives small. The shredded material is by appropriate Conductors forwarded.

From DE-PS 36 26 456 knives with rectangular cross sections are known to the have their longitudinal sides ground cutting edges, extending over approximately Three quarters of the length or even over the entire length of a knife erstrekken.

Known from EP 0 538 599 and DE-U-94 16 851 are knives to which Cutting edges serrations are ground. Due to the fact that the cutting edges through Loops are produced results under load of the knives for a possible Deformation of the cutting tools unfavorable voltage curve, since the bevelled Surfaces are produced by a material-separating machining, through which not only grooves are formed on the surface of the inclined surfaces, the one Notch effect favor, but also the fiber or texture course of the usual broken knife made of strip material is interrupted.

The service life and stability of such knives significantly determine the reliable Function of chopping devices, which only work without vibrations, when the rotating drums are equipped with equally heavy cutting tools are. Must z. If, for example, a broken knife is to be replaced, so must the the opposite side of the drum arranged knives are replaced, to restore balance.

The invention

The object of the invention is therefore, for Häckselvorrichtungen a chopper and to propose a manufacturing method for this, by the cutting edge and Resistance to bending, twisting and breaking significantly improved become. Chopping blades also need to be manufactured in extremely tight weight limits become. The production must be process-reliable. According to the invention this Problem solved by the features of claims 1, 15 and 22, respectively.

Knife for shredders need not be particularly sharp, but possible have durable resistant cutting edges. To achieve this result, In the past, the knife's longitudinal edges were prism-shaped and ground then the entire knife hardened. It turned out that a sanding step for the entire knife can be omitted if the prism-shaped Cutting edges produced by a rolling process by way of material deformation be, with a slightly rounded, sufficiently sharp but resilient Cutting edge yields. In such cutting edges cracks and resulting accounts Fractures, as in material-removing processing by grinding or the like were favored.

According to the invention is preferably a strip material, ie a flat steel for the production used the cutting tools. The lateral edges (longitudinal edges) of the Band material receive one-sided or two-sided inclined surfaces, in particular by Cold rolling, so by a forming process. The bevels can vary in different Be arranged so that trapezoidal, parallelogram or double wedge-like Cross sections of the knife result. But also other cross-sectional training are possible, the z. B. by uneven chamfers or combinations different profiles arise.

In an advantageous embodiment of the invention, the cutting edge with a radius provided by <0.3 mm. By this design, such a cutting edge is present Foreign body damage less sensitive than a sharpened edge. Furthermore, the service life of such an edge is increased. The rounding of a previous one sharp edge results anyway after a short operating time. In addition, distributed The impact force on a knife edge of the type described above much better as on a sanded edge when the drum of the shredder comes to a standstill and the swinging knives lead by their centrifugal force, and hit with their cutting edges on the drum cylinder.

If, as preferred, the forming of the longitudinal edges of the flat steel by rolling along the entire flat steel length, this step is not only special economically, but the knife gets on its entire length one through the deformation-induced rolling texture increased edge strength.

With chopper knives, extremely narrow weight limits are of the order of magnitude of +/- 1 gram per knife. This very difficult task could in the past through the grinding process when manufacturing prism-shaped Cutting edges are maintained with some effort. It has been shown that in the Rolls according to the invention of the cutting edges until sufficient sharpness, ie avoiding the Anwalzens it is extremely difficult to narrow the weight limits to ensure. According to a development of the invention therefore different Steps - also individually or in combination with each other - suggested: If the Longitudinal edges of a rectangular in cross-section starting material before forming be machined to prism-shaped cutting edges by rolling, This can not only be an advantageous for the subsequent rolling smoothing of Cutting edges are achieved, but also a cross-sectional correction of the starting material, which is advantageous for the subsequent weight stability. This particular then, if the starting material of a so-called broadband flat steel is made by longitudinal gaps. A machining step to the Long edges can therefore the edge cleaning and / or the vote of the Serve cross-section volume.

To prismatic formed by rollers to cutting edges until sufficient sharpness Cutting high quality, it is of particular advantage when the Longitudinal edges of a rectangular in cross-section starting material by edge rolling be smoothed out first. As a result, the microstructure of the cutting edge becomes significant improved.

To the weight-bearing capacity, in particular the cross-sectional volume in the for rotating It is particularly advantageous to if between successive pairs of profile rolls for forming the Longitudinal edges to prism-shaped cutting by rolling to sufficient Sharp rollers are used for width calibration. This will cause the material flow between successive pairs of profiled rollers controlled in a manner which promotes the formation of high quality rounded cutting edges.

The wear behavior of chopping blades according to the invention can continue - and indeed also independent of the features of claim 1 - thereby improved be that at least one hard metal piece is inserted into the cutting edge. so trained chopping blades are of independent inventive importance. The Carbide can - but does not necessarily have - due to its own cutting edges on Actively participate in the chopping process. If such a cemented carbide insert near the free end of the chopper blade is thereby the wear of the Total cutting edge counteracted significantly, because at this point the loads by foreign bodies of greater hardness, such as small stones, is the largest. Such carbide inserts usually have a greater width than that The cutting edge and are therefore particularly well able to throw away foreign objects. Such carbide inserts affect because of their width on the Degree of destruction of the surface of the shredded material advantageous.

If, according to another embodiment of the invention, several cutting blades to a cutting knife package are combined, creates a total of thicker Cutting knife, with several approximately parallel to each other aligned cutting edges. Such an arrangement, which can be advantageously used without the features of claim 1 is, not only leads to a greater shredding of the shredded material, but also to a better destruction or at least injury of the outer skin layers or cell structures of the shredded material, whereby z. B. the rotting behavior the shredded material is improved.

A possible embossing step for cross-sectional profiling of the knife for stiffening in the longitudinal direction is preferably after the production of prism-shaped Cutting edges performed by the rolling process. By the embossing step about occurring Längskantenverbiegungen affect the rolling step so not detrimental out.

Particularly economical is the production by the process according to the invention, if a steel strip along its one or preferably its two longitudinal edges continuous with prism-shaped cutting edges by appropriately profiled Rollers provided and the chopping blades by separating sections suitable Length and subsequent processing are produced.

Overall, the invention thus provides sufficient sharpness of the chopper blade achieved along both longitudinal edges on the full length and an energy and time-consuming grinding operation as well as grinding-related damage to the texture avoided.

The above-described invention is not only suitable for rotating drums moving chopper, but also for in the axial gap between these moving chopping knives engaging counter knife. Accordingly, refers the invention also to the chopper as such.

The invention thus overcomes difficulties that are contradictory Requirements are triggered. Through the profile rolling until sufficient Sharpness becomes a cutting edge grinding the associated structural damage avoided in the cutting edge area. However, chaff in very tight weight tolerances even without the known in the prior art correction option achieved by cutting edge grinding when calibrating Rolling steps are made on the longitudinal edges.

The aforementioned and the claimed and described in the embodiments According to the invention components to be used are subject in their size, Form design, material selection and technical conception no special conditions of exception, so that the selection criteria known in the field of application be fully applicable.

Further details, features and advantages of the subject invention from the subclaims and from the following description of the associated Drawing, Fig. 3 to Fig. 11 B, in the - exemplary - preferred embodiments Chopping knife according to the invention are shown. In the drawing show:

Brief Description

Fig. 1

a chopping knife according to the prior art with two ground Cutting edges in perspective view;

Fig. 2

the section A'-B 'through the knife shown in Figure 1;

Fig. 3

a chopper knife according to the invention with two by cold forming produced cutting edges in a perspective view;

Fig. 4A to Fig. 4F

six cross sections through chopper with by cold or hot forming produced bevels;

Fig. 5 A

a double wedge-like cross section through a chopper with through Cold or hot formed inclined surfaces and rounded Cutting edges without embossing;

Fig. 5B

another chopping knife in a perspective view with embossing;

Fig. 5C

another chopping knife with different carbide cutting inserts;

Fig. 6

a cross-sectional view (polished section) of an inventive Rolling up to sufficient sharpness transformed prism-shaped Cut with slightly rounded cutting edge with a cutting edge radius of about 0.25 mm;

Fig. 7

a chopping blade 2 in 2 consisting of two chopping knives 2A, 2B perspective view (a), in plan view (b) and in front view (c);

Fig. 8

another from two knives 2A, 2B existing chopper 2 in Top view (a), in side view in gap-free assembly (b) or spaced assembly (c) and in front view (d) without Distance and (e) by far;

Fig. 9

a section of a chopping device with stationary and moving Knives in the form of chopper packages in front view;

Fig. 10A / B

a double-edged chopper knife in U-shape in plan view of the Cutting edges (Fig. 10A) and in perspective (Fig. 10B) and

Fig. 11A / B

two more chopping blades in plan view with undercut-like front edge

Detailed description of the embodiments

The chopping blades 1 and 2 shown in perspective view in FIGS. 1 and 3 have a circular opening 3, which serves the swinging attachment. If that Knife is not hinged, but fixed fixed, becomes another circular Opening 4 (Fig. 3) is provided.

The prior art knife 1 shown in FIG. 1 has two cutting edges 5 and 6 which extend over approximately three quarters of the total knife length. These cutting edges are formed by the oblique poles 7 and 8 or 9 and 10 (FIGS. 1 and 2).

The knife according to the invention shown in Fig. 3 by cold or hot forming produced inclined surfaces 11 and 12 or 13 and 14, which are the cutting edges 15 or 16 form. The inclined surfaces 11 and 12 or 13 and 14 extend over the entire knife length. The cutting edges 15 and 16 (Fig. 5 A) each have a rounding R up. Also, the knife cross sections a to f shown in FIG. 4 have at their cutting edges 17 to 28 curves, because of their small Size in Figures 4A to 4F are not visible.

A chopper knife with a stiffening longitudinal embossing is shown in Fig. 5 B can be seen. The prism-shaped blades are in the front area with ground saw teeth superimposed.

Fig. 5C shows a chopper with inserted carbide pieces 30. By way of example a single carbide blade 30A and a twin hard metal blade 30B, 30C shown in the top area. The latter can replace double-blade chopping blades as shown below in FIG. 7 or FIG. 8.

In the embodiment according to FIG. 7, the chopper blade 2 consists of two according to the invention trained chopping knives 2A and 2B, which in the exploded view (a) and (c) are still shown at a distance from each other. The identical Knives are z. B. joined together by riveting in tight support. The end area near the hole 3 for knife attachment is rounded semicircular. In contrast, the chopper blade of Fig. 8 is lenticular rounded in this area, wherein the embodiment according to paragraph (c) or (e) via spacers 32nd have an increased width.

Finally, Fig. 9 shows an arrangement of chopping blades 2 in a device at a fixed counter knife 2 'in the gap A gap of the moving chopper 2 engages. The chopping blades 2 consist of packages of 3 chopper knives each 2A, 2B, 2C, while the fixed counter knife from a package of two Knives 2'A, 2'B exist. Each of these chopper knives and counter knives has several laterally spaced cutting, which for a greater crushing or refraction of the shredded material and improved destruction of the surface structure of the Shredded material are beneficial.

The further chopper blade according to FIGS. 10A / B is a twin chopper knife the one-piece from a correspondingly long section by bending is formed to the U-shape and aligned with each other at its attachment end Mounting holes 3 is provided. Such a chopper is distinguished by special torsional stiffness. As shown and preferred to that extent is the U-shaped bridge area 2D between the two straight stretched chopper blades 2A and 2B are also provided with a cutting edge 15 ', 16' which complete the slits 15 and 16. It can be seen that with a bridge area Twin chopping knives connected at their free ends, spaced laterally are arranged parallel to each other, also in other than that shown in Fig. 10A Way can be connected in the bridge area, as by a spacer, which by gluing, welding, or the like connected to the Häckselmesserenden can be. - Such twin chopper are also without the features of claim 1 of independent inventive significance.

The exemplary embodiments according to FIGS. 11A / B show, on the one hand, that for avoidance Of cutting waste, the knife end faces can be complementarily shaped (separation edges 34A and 34B). In this way, chaff knives from a flat band be obtained without waste. The material savings can be up to about 8%. Furthermore, it can be seen that the knife end faces can have free surfaces 33. D. h., That the free ends of the cutting edges 15 and 16 a Messerflugkreis X describe while the other end face areas jump back. Around Sloping surfaces 11 to 14, the free surfaces 33 may be provided as a straight undercut whose angle to the cutting edge is less than 90 degrees. such Open spaces are known from cutting tools. In the middle knife area the undercut can also be concave, as in FIG. 11A or stepped, as in FIG. 11B be executed.

LIST OF REFERENCE NUMBERS

2

chopping blades

2A, 2B, 2C

chopping blades

2D

bridge area

2 '

against knife

2'A

against knife

2 B

against knife

3

Circular opening

11

sloping surface

12

sloping surface

13

sloping surface

14

sloping surface

15

cutting edge

15 '

cutting edge

16

cutting edge

16 '

cutting edge

17-28

cutting edges

30

Carbide cutting

30A

Carbide cutting

30B, 30C

Twin carbide cutting edge

32

spacers

33

front edge

34A

tear-off

34B

tear-off

R

curve

A

spacing gap

X

Cutting circle

Claims (30)

Method for producing knives of steel for devices for cutting straw and the like, equipped with rotating drums on which the knives are fixed or oscillating,
characterized in that a ribbon-shaped present flat steel is formed at least one of its longitudinal edges to the prism-shaped edge with a slightly rounded cutting edge by rolling to sufficient sharpness. A method according to claim 1, characterized in that the deformation takes place by cold rolling. A method according to claim 1 or 2, characterized in that the deformation takes place along the entire length of the flat steel. Method according to one of claims 1 to 3, characterized in that the longitudinal edges of the cross-sectionally preferably rectangular starting material are machined before the rollers, Method according to one of claims 1 to 4, characterized in that the necessary cross-sectional volume of the flat steel is adjusted by machining the longitudinal edges. Method according to one of claims 1 to 5, characterized in that the longitudinal edges of the starting material are smoothed by edge rolling. Method according to one of claims 1 to 6, characterized in that edging rollers are used for width calibration between successive pairs of profile rollers for rolling prism-shaped cutting. Method according to one of claims 1 to 7, characterized in that the cutting edges after the rolling process have a cutting edge radius of at most 0.3 mm. Method according to one of claims 1 to 8, characterized by an embossing step for cross-sectional profiling of the knife. Method according to one of claims 1 to 9, characterized in that after the production of the prism-shaped cutting edges tooth cutting in at least a partial length of the prism-shaped cutting edge, in particular by grinding, are introduced. Method according to one of claims 1 to 10, characterized by a zone-hardening step along at least a partial length of the prism-shaped cutting edge region, in particular by way of inductive zone heating. Method according to one of claims 1 to 11, characterized in that a flat steel strip is provided over a greater length with the rolled cutting edges and is subsequently subdivided by cross-cutting in choppers further processed sections. Method according to one of claims 1 to 12, characterized in that in the prism-shaped cutting edge at least one cutting or non-cutting hard metal piece is used to reduce wear. Method according to one of claims 1 to 13, characterized in that several knives are joined together to form a correspondingly thicker knife package. Steel chopping knives for apparatus for cutting straw and the like, fitted with rotating drums on which knives are fixed or oscillating, consisting of a section of flat steel with a fixing zone, such as a perforation, and a prism-shaped at least on the longitudinal edge , optionally provided with tooth cutting edge, characterized in that the at least one prism-shaped cutting edge has a extending over at least a partial length of the longitudinal edge rolling texture with prism-shaped arrangement of the rolled surface zone. Chopper knife according to claim 15, characterized in that the rolling texture extends over the entire length of the knife at both longitudinal edges. Chopper knife according to claim 15 or 16, characterized in that the rolling texture is superimposed on tooth-shaped cutting edges in the region of the prism-shaped cutting edges. Chopper knife according to one of claims 15 to 17, characterized in that the longitudinal edges / rolling texture is superimposed by a hardening structure. Chopper knife according to one of claims 15 to 18, characterized by a longitudinal profiling, in particular a longitudinal embossing of the chopping knife. Chopper blade according to one of claims 15 to 19, characterized by at least one cemented carbide insert in the cutting edge. Chopper knife according to one of claims 15 to 20, characterized in that there is a plurality of combined to form a package knife. Chopper knife according to one of claims 15 to 21, characterized in that the knife end faces are provided with an undercut. Chopper knife according to claim 22, characterized in that the undercut has at least one free surface (33). Chopper blade according to claim 22 or 23, characterized in that the undercut has a concave or stepped portion. Chopper knife according to one of claims 15 to 24, characterized in that the Häckselmesserstirnseiten are complementarily shaped. Chopper knives, in particular according to one of claims 15 to 25, characterized by two chopper knives arranged at a distance from one another with a bridge region connecting the free chopper blade ends. Chopper blade according to claim 26, characterized in that the bridge region is U-shaped and connects the two chopper knives integrally with each other. Chopper blade according to claim 26 or 27, characterized in that the bridge region is provided with at least one cutting edge. Steel counter-knives for straw cutting devices and the like equipped with rotating drums on which knives are fixed or oscillating, the counterknife engaging in the axial spacing gap (A) of adjacent knives, consisting of a section of flat steel with one Fastening zone, such as a perforation, and provided at least on the longitudinal edge prism-shaped, optionally provided with tooth cutting edge, characterized in that the at least one prism-shaped cutting edge has over at least a partial length of the longitudinal edge extending rolling texture with prismatic arrangement of the rolled surface zone. Counter knife according to claim 29, characterized by at least one of the characterizing features of one of claims 15 to 28.

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